This version of VW's engine management system is On Board Diagnostic II (OBD II) compliant. Both the 1996-99 2.0 liter and the VR6 engines are equipped with this system. As of 1995, the Government mandated that all vehicles sold in the U.S. must have an engine operating system that complies with OBD II standards. Several changes were made to the Motronic system that enabled it to meet the necessary requirements. One change between this system and the Motronic 2.9 is that there are two Heated Oxygen Sensors (HO2S) on this type system, one pre-catalyst (before the catalytic converter) and one post catalyst (after the catalytic converter).